Methods of machining combs for musical mechanisms

ABSTRACT

A comb blank is given two inclinations relative to the rotational axis of a spindle carrying a plurality of spaced rotatable tools of equal diameter. The comb blank is then passed relative to the tools when rotating so that a plurality of parallel tongues are formed in the comb blank from one end of the comb blank towards the opposite end. The relative inclinations are so arranged that a line joining the roots of the tongues where the tongues join the remainder of the comb blank forms a predetermined angle with the one end of the comb blank.

United States Patent Matthey 51 Mar. 7, 1972 [54] METHODS OF MACHINING COMBS [56] References Cited FOR MUSICAL MECHANISMS UNITED STATES PATENTS [721 Emile Mam! switzer'and 1,645,181 10/1927 Consoli ..9o/11 B [73] Assignee: Matthey S.A., Vuiteboeuf, Switzerland 2,838,834 6/1958 Ganine ..29/ 169.5 [22] Filed: June 1970 Primary Examiner-Francis S. l-lusar [21 AppL No; 45,726 Attorney-Robert E. Burns and Emmanuel J. Lobato ABSTRACT [30] Forelgn Applicamn Priority Data A comb blank is given two inclinations relative to the rota- June 16, 1969 Switzerland ..9l37/69 tional axis of a spindle carrying a plurality of spaced rotatable tools of equal diameter. The comb blank is then passed rela- [52] US. Cl. ..90Ill C, 90/11 B, 84/94, tive to the tools when rotating so that a plurality of parallel 83/56, 83/488, 83/908, 51/327, 29/ 169.5 tongues are formed in the comb blank from one end of the [51] Int. Cl. ..B23c 3/00 comb blank towards the opposite end. The relative inclina- [58] Field of Search ..29/ 169.5; 51 [327,281 R, 326; tion are so arranged that a line joining the roots of the tongues where the tongues join the remainder of the comb blank forms a predetermined angle with the one end of the comb blank.

7 Claims, 3 Drawing Figures METHODS OF MACHINING COMBS FOR MUSICAL MECHANISMS BACKGROUND OF THE INVENTION The tongues of combs for musical mechanisms should have a progressively decreasing effective length, and the anchor line of the tongues, that is, the line joining the roots of the tongues is so formed, as to form with the front edge of the comb a predetermined angle.

It is known for tongues to be cut out either by means of a set or cluster of milling cutters, each with a different diameter, mounted on a common spindle, or by means of a set of cutters milling several combs at the same time, these combs being staggered by the same number as there are tongues. In both these known methods, the cutting of the comb blank is started at an edge. The tongues are cut from their outer ends towards their anchor points which makes the tongues flex under the action of the cutters. This tends to deform or even break the tongues.

It is also known to work a plate consisting of a double blank at right angles to its surface in such a way as to simultaneously mill the tongues of two .combs and then separate them. This last method, however, is very slow because of the method of cutting the blank. On the other hand, the grinding process known as crushing consists of using a shaped grinding tool, the profile of which is continually kept in shape by a shaped cutting wheel.

AIMS OF THE INVENTION An object of the present invention is to provide a method of manufacturing a comb for a musical mechanism by grinding or milling, which enables cutting tools of the same diameter or a shaped grinding wheel with a cylinder jacket to be used.

A further object of the invention is to provide a method whereby the comb blanks are cut in a direction from the anchor points of the tongues towards the free ends of the tongues, thereby minimizing the flexing of the tongues during the machining operation.

According to the present invention, a method of machining a workpiece in which the workpiece is moved relatively passed a plurality of spaced circular tools of equal diameter mounted for rotation on a rotatable spindle comprises relatively inclining the workpiece at a predetermined angle to the vertical plane at right angles to the vertical plane containing the axis of rotation of the spindle, relatively inclining the workpiece at a predetermined angle to the vertical plane containing the axis of rotation of the spindle, and moving the workpiece relatively passed the tools when rotating so that a plurality of parallel tongues are formed in the workpiece from one end of the workpiece towards the opposite end, and whereby a line joining the roots of the tongues with the remainder of the workpiece forms a predetermined angle with said one end of the workpiece.

DESCRIPTION OF DRAWING An embodiment of the invention will now be described, by way of example, reference being made to the accompanying drawing in which:

FIG. I is a plan view of a comb for musical mechanisms,

FIG. 2 is a view of the comb of FIG. 1 in the direction of arrow F, and

FIG. 3 is a side elevation of the comb of FIG. 1.

As shown in the Figures, a musical comb has 12 tongues, the anchor line forming an angle of 15 with the front edge of the comb. The rotational axis of the milling cutters 2 is indicated at 1. All the milling cutters 2 used are of the same diameter and are mounted on a spindle (not shown), the milling of the comb being carried out in the direction of the arrow F in such a way that the operation begins with cutting the roots of the tongues and progresses towards the front edge of the comb. FIG. 1 shows the relative position of the comb and the rotational axis of the milling cutters in a vertical projection.

In order to obtain the desired angle of 15, the rough blank of the comb is given a first inclination of an angle of A relative to the vertical plane at right angles to the vertical plane containing the rotational axis 1 as shown in FIG. 2, and a second inclination of an angle B relative to the vertical plane containing the rotational axis 1. In the example shown in the drawing, the angle A is 130 and angle B is 6. This inclination can be given either to the comb blank when mounting the comb blank, or to the milling cutters which are for this purposes mounted on an adjustable sliding block on a slide, the support for which has the two inclinations A and B.

Since the tongues of the comb are machined in the direction of arrow F, that is from their roots to their free ends, they have a considerable rigidity and less risk of bending and being deformed which enables them to be milled with an increased cutting speed. Since the milling cutters are all the same diameter and the same thickness, it is possible to employ crossmembers of greater diameter which increases the rigidity of these tools and the precision of the work. It should be understood, however, that it is possible to mill from the free ends to the roots of the tongues, if required.

The cutting out of the tongues by grinding is generally reserved for combs for musical movements with two or more tones in which the tongues of the combs have a wider spacing and which permits the use of the grinding wheels existing on the market. The principal advantage of shaping by grinding lies in the fact that the comb can be tempered before shaping so as to obviate any risk of deformation after shaping. The only remaining operation is then the tuning of the comb.

In addition, it is possible to rationalize the machining operation further by placing several comb blanks side-by-side in such a way that they are successively machined by one pass.

In the example described, it is to be understood that the blank was worked on its upper surface but it is also possible to work the comb blank on its lower surface, the comb being, of preference, turned round for this purpose.

What is claimed is:

1. In a method of machining a workpiece in which the workpiece is moved relatively past a plurality of spaced circular tools of equal diameter mounted for rotation on a rotatable spindle, the improvement which comprises relatively inclining the workpiece at a predetermined angle to the vertical plane at right angles to the vertical plane containing the axis of rotation of the spindle, relatively inclining the workpiece at a predetermined angle to the vertical plane containing the axis of rotation of the spindle, and moving the workpiece relatively past the tool when rotating so that a plurality of parallel tongues are formed in the workpiece from one end of the workpiece towards the opposite end, and whereby a line joining the roots of the tongues with the remainder of the workpiece forms a predetermined angle with said one end of the workpiece.

2. In a method of machining combs for musical mechanisms in which a comb blank is moved relatively past a plurality of spaced circular tools of equal diameter mounted for rotation on a rotatable spindle, the improvement which comprises relatively inclining the comb blank at a predetermined angle to the vertical plane at right angles to the vertical plane containing the axis of rotation of the spindle, relatively inclining the comb blank at a predetermined angle to the vertical plane containing the axis of rotation of the spindle and moving the comb blank relatively past the tools when rotating, so that a plurality of parallel tongues are formed in the comb blank from one end of the comb blank towards the opposite end, and whereby a line joining the roots of the tongues with the remainder of the comb blank forms a predetermined angle with said one end of the comb blank.

3. A method as claimed in claim 2, wherein the tools are circular milling cutters.

4. A method as claimed in claim 2, wherein the comb blank is first tempered and the tools are circular grinding wheels.

5. A method as claimed in claim 2, wherein the comb blank relatively passes the circular tools with the opposite end first.

6. A method as claimed in claim 2, wherein a plurality of comb blanks are clamped together and machined successively in one pass.

7. A comb for a musical mechanism made by the method as claimed in claim 2. j 5 

1. In a method of machining a workpiece in which the workpiece is moved relatively past a plurality of spaced circular tools of equal diameter mounted for rotation on a rotatable spindle, the improvement which comprises relatively inclining the workpiece at a predetermined angle to the vertical plane at right angles to the vertical plane containing the axis of rotation of the spindle, relatively inclining the workpiece at a predetermined angle to the vertical plane containing the axis of rotation of the spindle, and moving the workpiece relatively past the tool when rotating so that a plurality of parallel tongues are formed in the workpiece from one end of the workpiece towards the opposite end, and whereby a line joining the roots of the tongues with the remainder of the workpiece forms a predetermined angle with said one end of the workpiece.
 2. In a method of machining combs for musical mechanisms in which a comb blank is moved relatively paSt a plurality of spaced circular tools of equal diameter mounted for rotation on a rotatable spindle, the improvement which comprises relatively inclining the comb blank at a predetermined angle to the vertical plane at right angles to the vertical plane containing the axis of rotation of the spindle, relatively inclining the comb blank at a predetermined angle to the vertical plane containing the axis of rotation of the spindle and moving the comb blank relatively past the tools when rotating, so that a plurality of parallel tongues are formed in the comb blank from one end of the comb blank towards the opposite end, and whereby a line joining the roots of the tongues with the remainder of the comb blank forms a predetermined angle with said one end of the comb blank.
 3. A method as claimed in claim 2, wherein the tools are circular milling cutters.
 4. A method as claimed in claim 2, wherein the comb blank is first tempered and the tools are circular grinding wheels.
 5. A method as claimed in claim 2, wherein the comb blank relatively passes the circular tools with the opposite end first.
 6. A method as claimed in claim 2, wherein a plurality of comb blanks are clamped together and machined successively in one pass.
 7. A comb for a musical mechanism made by the method as claimed in claim
 2. 